At present, with the gradual consumption of non-renewable energy such as oil and with the urgent need for environment protection, the development of new energy industry has drawn great attention. One of the key and core technologies of the new energy industry is the battery. New energy vehicles which use rechargeable batteries as power source have achieved rapid development in recent years, the proportion of new energy vehicles in the vehicles all over the world is gradually expanded, and they are widely used in large and medium-sized cities, which is an important part of developing the electric vehicle industry and realizing advanced manufacturing in our country.
Most of the current electric vehicles use charging piles to charge a battery at a constant current. When adopting the charging method, since under different states of charge (SOCs), a rechargeable battery can actually bear different charging currents, resulting in that the charging efficiency of constant current charging is relatively low. In addition, if the rechargeable battery is charged under too high or too low a temperature, the method of constant current charging may have a negative effect on the service life of the battery.